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In Vivo Analysis of Acromioclavicular Kinematics and Distance During Multiplanar Humeral Elevation
Siyuan Zhu1,2, Yuzhou Chen1,2, Peng Wang1,2
1Department of Orthopaedic Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
The American Journal of Sports Medicine
|January 10, 2024
Summary
This study reveals how the acromioclavicular (AC) joint moves and changes distance during arm elevation. Findings provide crucial biomechanical data for understanding AC joint function and developing better treatments.
Area of Science:
- Orthopedics
- Biomechanics
- Human Anatomy
Background:
- Accurate in vivo data on acromioclavicular (AC) joint kinematics and distance are lacking.
- Understanding AC joint biomechanics is crucial for developing effective treatment methods.
Purpose of the Study:
- To investigate 3D AC joint kinematics and distance during arm elevation in healthy individuals.
- To determine how arm elevation angle and plane affect AC joint motion and spacing.
Main Methods:
- Dual fluoroscopic imaging and CT were used to analyze AC joint motion in 19 healthy shoulders.
- Measured AC joint rotation, translation, and the minimum distance between the acromion and clavicle.
Main Results:
- Progressive rotation and translation of the AC joint were observed across all elevation planes.
- AC joint distance decreased with elevation angle up to 75°, varying significantly by plane.
- The minimum distance point shifted anteriorly with increasing elevation.
Conclusions:
- The AC joint exhibits significant rotation and translation during arm elevation.
- AC joint distance changes predictably with elevation angle and plane.
- These findings establish benchmark data for AC joint abnormality treatments.
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